Rock is an indefinite mixture/aggregate of naturally occurring materials that mainly include minerals. Rocks from which minerals or metals can be mined for economic purposes are called ores. Man-made materials having properties similar to rock include concrete and asphalt.
Certain machines allow rock or like materials to be excavated from the earth's surface. Examples of this type of excavation machine include surface excavation machines (e.g., surface mining machines) and trenchers.
Surface excavation machines are used to level terrain and/or remove a layer of material from a given site location. Typical applications include surface mining, demolishing a road, and prepping a site for new construction or reconstruction. Example rocks that are excavated using surface excavation machines include limestone, gypsum, bauxcite, phosphate and iodide. Materials (e.g., ores) such as copper, iron, gold, diamonds and coal can also be excavated using surface excavation machines. Surface excavation machines provide an economical alternative to blasting and hammering. Furthermore, surface excavation machines provide the advantage of generating a consistent output material after a single pass. Therefore, surface excavation machines can reduce the need for primary crushers, large loaders, large haul trucks and the associated permits to transport materials to crushers.
A typical surface excavation machine includes a main chassis supporting an operator cab. The main chassis is supported on a ground drive system such as a plurality of tracks. An engine such as a diesel engine is mounted on the main chassis. The engine provides power for driving the various components of the machine. Often, the diesel engine powers a hydraulic system which includes various hydraulic motors and hydraulic cylinders included throughout the machine. An excavating tool is typically mounted at a rear end of the main chassis. The excavation tool can include a rotational excavating drum mounted on a pivotal boom. The excavating drum carries a plurality of cutting tools (e.g., carbide tipped teeth) suitable for cutting rock. An example surface excavation machine of the type described above is disclosed at U.S. Pat. No. 7,290,360, which is hereby incorporated by reference in its entirety.
Trenchers are used to excavate trenches in rock. Often, the trenches are excavated for the purpose of installing utilities/product such as electrical cable, fiber optic cable or pipe. A typical trencher can have the same basic components as a surface excavation machine, except the boom and excavating drum is replaced with a trenching attachment. The trenching attachment includes a boom on which a digging chain is rotatably mounted. Cutting tools suitable for cutting rock (e.g., carbide tipped teeth) are carried by the digging chain. An example surface excavation machine of the type described above is disclosed at U.S. Pat. No. 5,590,041, which is hereby incorporated by reference in its entirety.
Surface excavation machines and trenchers excavate rock using a process characterized by relatively high tooth loadings (e.g., via high horsepower and high weight provided to the teeth) and relatively low tooth tip speed. This type of excavation technique combined with the non-uniform nature of rock causes relatively high force, high displacement shock pulses to be transferred to the main chassis and cab as relatively large pieces of material are removed (e.g., torn, ripped, etc.) from an excavation location during excavation operations.